As we move into the winter months and temperatures drop it’s not only builders and plasterers who don’t like the cold, the materials they are using don’t either. All cementitious products including Rendering Systems are affected by a drop in temperature, particularly when they are in a wet mixed condition. Here at CES Hire we often get phone calls asking us ‘Can render be applied in the winter?’ Obviously there are a few points to consider please read on below as we outline what the 3 biggest scratch render suppliers Weber, Krend and Parex suggest…
Weber, Krend and Parex all recommend that wet material should not be applied in temperatures below 5°C or if low temperature can be expected during the drying and curing period. If a frost is forecast during the day or overnight you must make sure work is completed in time to allow the material to set sufficiently to prevent frost damage. You can protect from frost by using polythene sheeting which can also be part of the scaffolding system. Your sheeting should hang clear off the wall in a way that it does not form a tunnel where wind could increase the evaporation of water from the render. The polythene sheeting must not be in contact with the render as this could produce a patchy appearance.
Do not apply render whilst it is raining. This includes if rainfall is forecast during your initial set or once you have newly applied material on the wall. They’re not just saying this to stop your applicators getting wet it is in fact to stop the render being inconsistent, weak or even washing off the wall. This is particularly important if strong colours in cementitious products are being used. When it is wet it’s very important not to render onto saturated backgrounds as this can reduce bond strength and cause unsightly lime bloom to occur. Obviously there are methods of keeping walls and render dry by using sheeting or roofing systems on your scaffold. These should be considered if working to a tight deadline but please make sure there are no leaks to your covering system.
When applying render in winter it is important to use good judgement. We recommend using a couple of local weather forecasts for advance knowledge and guidance on future weather and temperature conditions. If there is any doubt, we recommend you postpone applying your render and seek advice from Krend, Parex, Weber or whichever render manufacturer you have used.
You can find Parex, Krend and Weber Winter Rendering guidelines below…